Eskom has said stage 4 load shedding was caused by jellyfish and fish clogging up a drum filter at Koeberg nuclear power station’s Unit 1.
The struggling power utility made the revelation in an update on Thursday evening, adding to its illustrious list of load shedding causes that has included wet coal and sabotage.
It said Unit 1 had to be manually tripped according to standard procedure because of rising temperatures caused by “degraded heat removal (cooling) capability.”
‘Stage 4 load shedding until Friday evening’
Eskom added, “The circulating cooling water system pump that tripped was due to low level in the suction pit as a result of the drum filter that was clogged by an acute ingress of marine life (jellyfish and fish).”
It said normally, Koeberg’s units, which are located outside Cape Town next to the sea, are able to survive such a trip. However, Unit 1’s heat exchanger was experiencing “reduced efficiency.”
“The excess marine life and debris has been cleared off the drum filter and it is back in service. The level in the suction pit has sufficiently recovered and the circulating water system pump has been put back in service and no anomalies have been noted,” Eskom added.
It said the required approvals have been obtained to return Unit 1 back on the grid and that stage 4 load shedding would continue until Friday evening. Reduced stages of load shedding may continue into the weekend.
Wet coal, sabotage, conveyer belt
In October last year, Eskom said a conveyer belt fault at Medupi power station, in addition to “coal and ash handling issues,” had caused load shedding.
In December, it briefly implemented an unprecedented stage 6 load shedding and blamed “incessant rains” and flooding at some power stations for causing “wet coal.”
In a subsequent briefing to the nation, President Cyril Ramaphosa said possible acts of sabotage could have contributed to the load shedding crisis.
He said, “Someone in the Eskom system disconnected one of the instruments, which finally led to one of the boilers tripping.”
The Cabinet has since adopted a range of measures to address the country’s energy crisis, including allowing private companies to generate their own electricity for self-use.
It also decided that the government should procure additional electricity capacity to allow Eskom to take out some power units from service for much-needed maintenance.
In his State of the Nation Address (SONA) in February, Ramaphosa also announced that municipalities will soon be allowed to purchase electricity directly from independent power producers.